Hiding My Heart
by sometimes.it.lasts.in.love
Summary: <html><head></head>MerDer fic...may become a ficlet. Mer is in med school and she is dating her brothers best friend, Derek, without her brother knowing. Mark is Mer's brother. Lexie, Alex, Izzie, Cristina are all in it and are Mer's friends. AU</html>
1. Chapter 1 Secrets

**A/N: Okay...this is just an idea that came into my head that I can't seem to shake. So please tell me if the story sucks, cause I woke up this morning and just decided that I had to write it, when i should be updating my other fic, One And Only. So to be honest, I won't mind if you tell me it sucks. Then I can be done with this story and focus on my other one :) Or, I can keep working on both. It's your choice, so let me know what you think in the reviews.**

**Anywaaay, some background information on the story: Meredith is 3rd year at med school at UW, Derek and Mark are best friends who live together and they are 3rd year residents at SGH. Mark and Meredith are brother and sister, and they are really close because they had to stick together to deal with their crap parenting. Lexie is in the story, she is Mer's friend and Alex is also Mer's friend. Lexie is a year younger than Mer. Okay, I think thats all you need to know. Geez, this is a long A/N. I'm sorry. Enjoy.**

**P.S. Sorry, this update is short, but it felt like a good place to leave it at the end, so i'll try to update again soon.**

Meredith gave Derek one last kiss on the cheek before she climbed out of bed, grabbing her clothes off of the floor. He opened his eyes and watched her pull on her jeans, propping himself up on one arm. "Are you sure you have to go?" He asked, giving her a seductive look with his eyes and flashing her a winning smile. Meredith sighed. She definitely didn't want to leave the gorgeous man lying in the bed beside her, but she knew she had to. "I have to leave before Mark wakes up, you know that." She pulled her shirt over her head, and quickly raked her fingers through her hair, trying to no avail to comb out the tangles. Derek chuckled. "Sorry about your hair." he said, trying to lighten the mood. Meredith smiled, remembering. "I'm not." She said with an even bigger smile. "Plus, I have classes this afternoon. I haven't done any study practically all week, and I need a nap, I don't want to be falling asleep during my anatomy lecture." "You could always nap here." Derek said suggestively. "Again, you know I can't. We've kept this a secret for so long, I don't want my brother to find out and screw everything up. You know how he is, he'll beat the crap out of you. And then his hand will be ruined so he won't be able to operate and he'll be even more pissed. Not to mention your face will be ruined to. Mark knows how to throw a punch." Meredith's mind automatically flashed back to the time when she was about ten when her alcoholic father had slapped her across the face for not buying alcohol when she and Mark went to the store. He had been about to punch her, when out of nowhere Mark swung Thatcher around to face him, and he punched him in the face giving him a black eye for a week. Meredith shook her head, hating her mind for taking her back to her horrific childhood. She once again thanked God for Mark, and hated herself for keeping secrets from him. Derek watched her facial expression change and he knew what she was thinking. Whenever she was thinking over her childhood her eyes would glaze over in a certain way and her mouth would fall from her usual smile to a hard line. "Mer, are you okay?" He said softly, but he didn't think she heard him. A few moments later, she shook her head, and when she stopped moving her mouth was in a soft smile and her green eyes were sparkling as usual. "Huh? Did you say something?" She said when she noticed the expectant look on Derek's face. "I just wanted to know if you're okay. You got that look on your face..." Derek said softly, tilting his head to the side in a way that made her mind go blank for a second. "There wasn't a look. There isn't a look." She said with a smile, leaning down to peck him on the lips.

"Oh, and can I borrow that big anatomy book you have? It was really good when I was studying here yesterday."

"Sure. Just keep it."

"Really? It must have cost like $150.00. I just need to borrow it for this one class..." "Meredith, just take it. It's not charity or anything, it's a gift. Since you don't like roses or anything else normal, just take the anatomy book." He said with a cheeky smile.

"Okay, fine." She said, giving him a small smile and twinkling her eyes in a way that made him want to pull her back down on the bed and kiss her until she couldn't breathe. He was about to reach for her when she spun around.

"Was that a noise? I heard a noise upstairs...I really have to go now."

"Mer, are you sure you can't just stay down here while i make breakfast? Mark never comes down here, both his room, the kitchen and the lounge are upstairs. He has no reason to come down."

"Nope. I'm leaving." She said defiantly, grabbing her bag off the floor.

Derek dropped his shoulders in defeat. "I'll call you?"

"You do that." Meredith said with a wink. She turned around and walked out the door, hips swaying as if to purposefully taunt him. She quickly slipped out the back door, and walked down the hill and around to the next street to her parked car. She didn't take any risks when it came to her and Derek's relationship. She wouldn't admit it to herself, but it meant so much to her that she would do pretty much anything to make sure Mark didn't find out and ruin it.

She kept telling herself it was about the sex. But even she knew, deep down, that it was a lie. She smiled to herself, even just thinking about him. When did she become this soft, corny, gooey person who swooned over a guy who was older and pretty much off limits since he was her brothers best friend. This wasn't her. She wasn't like this. She was Meredith Grey, the best in her class, the one that was always out partying, having meaningless one night stands. Until that one night stand with Derek turned into two nights, and then three nights, and now she couldn't stop thinking about him. She had always hated the type of girls who begged for attention from guys, the ones who fell in love with any guy who looked their way. She was not going to become one of them. She was going to break it off. Definitely. She was going to do it tomorrow. Feeling a sense of determination, she drove off, turning up her music till it was almost loud enough to drown out the thoughts of being without Derek.

**A/N: I hope Mer wasn't too sappy at the end, I don't want her to come off like that. Let me know what you think! :)**


	2. Chapter 2 Learn To Fly

**A/N: Thanks for the reviews, everyone who gave me one! Here is the next chapter...again, let me know if I should continue :)**

Derek lay there for a few minutes, knowing he should try and get some sleep before he had to go to the hospital, but his mind kept showing him Mer's face when she thought about her childhood, and he kept wondering what she was thinking about. She and Mark never talked about it to him, but he thought he knew what had happened from the few times he had spent the night at Marks house, or the many times he and his mother had picked up Mark to take him back to their house. He remembered that when Mark would leave, he would always spend about half an hour talking with Meredith. Derek had at first wondered why Mark bothered talking to his little sister, and why it took so long. But as he got older, he realised that Mark was calming her down, because she was so scared to be alone in the house with their father. More than a few times, Mark would cancel coming over for dinner or to stay the night, and he would give some lame excuse. Derek got mad a few times, but as he got older he realised that if Mark cancelled it was because Thatcher was so drunk the Mark was scared to leave him alone with Meredith. Mark would never admit that to Derek's face, but he managed to figure it out on his own. The signs were all there that Thatcher was an alcoholic, no matter how hard Mark tried to keep it from his friends at school and especially Derek. Derek opened his eyes and sat up, finally giving up on ever getting some sleep. He trudged up the stares and into the bathroom, splashing his face with cold water to get the sleep out of his eyes. He wandered into the kitchen, and found Mark making coffee and toast while reading a medical journal.

"I can so see you now, standing right there in that same spot with a wife making eggs and bacon and all your kids running around you. It's very domestic." Derek chuckled.

"Oh, that's so funny. I can see you years from now, looking the same, still trying to get through med school because you're to tired to pass the exams." Mark retorted with a smirk, and then he continued.

"Really, man, what time did you get home last night? And don't think I didn't hear you and that girl you brought home last night. Walking around the house, knocking things over. Man, how drunk were you?"

"Well, I, um, I honestly don't remember." Derek said, glad that Mark hadn't come out of his room last night to tell them to shut up. That would've be very bad.

"At least you weren't loud during the sex. I'll give you that." Mark said, handing Derek a coffee.

"Yeah, um, that's, I'm glad we didn't wake you." Derek mumbled.

"Geez, you are hung over. You're not a mumbler. You can barely get a sentence out!"

"Yeah, I'm pretty hung over...and tired."

"I'm sure you are." Mark replied. "I'm going into the hospital now, since you haven't even got dressed yet. I want to get on Dr. Jacobs service before anyone else does."

"Okay...wait, who is Dr. Jacobs?"

"Geez, man, you are out of it. He's the new plastics guy remember? World renowned surgeon? Whatever, I'll see you later." Mark said, shaking his head and walking out the door.

"Mer! You're here, thank God. Remember last month when they said they have a new policy saying that we have to tutor a 1st year if we want a shot at getting first of our class? And we thought they were kidding, so we just wrote our names down for a joke? Well, I just read the notices, and they want all tutor's of 1st year med students to meet in the main foyer!"

"Seriously? Crap, can we get out of it?" "No...but to be honest I don't want to. I have to be first in out class. And if that means tutoring some stupid first years, then I'll just...push through." Cristina said with a deep breath and a determined tone.

"Well, I'm not going to -"

"If i'm doing this, you are to." Cristina said with a death stare.

"Fine. But you owe me."

"Whatever."

"Hey Mer. Cristina." Alex said as he walked up to them. Cristina rolled her eyes in hello, and Meredith smiled.

"Hey, Alex, are you doing this

"Yeah, unfortunately. I thought it was a joke! I don't really mind though, maybe I might tutor some hot first year." "You, are disgusting." Cristina said raising her eyebrows/

Alex shrugged and looked at Meredith. She smiled and rolled her eyes.

"So, what class do you have next?" Meredith asked both of them.

"I don't have any classes till 3:00pm." Cristina said, a frown on her face.

"Anatomy. With, uh...Jones. You?"

"I have the same as you, Alex. I got that book he was talking about in class last week."

"Seriously? It cost like $150.00! Where did you get it?

"Uh, um, a friend. My brothers friend actually. Well, kinda my friend. Both of our friend really. Anyway, he gave it to me. Derek. His name is Derek."

Alex and Cristina exchanged a glance and burst into laughter.

'What, what is so funny?" Meredith said, looking between them.

"Oh, Meri's got a cruush." Cristina said in a teasing, sing song voice.

"Do you love him? Are you in loove?" Alex said, nudging her shoulder.

"I do not! He's just a friend, my brothers friend actually. Whatever." Meredith shrugged.

"Oh my God, you're blushing. We don't blush!" Cristina scolded.

"I'm not blushing! Can we just get to the meeting already!" Meredith said, trying to stop the redness on her cheeks. She pushed open the lobby doors, and looked around. Well this is going to be such fun, Meredith thought, watching all of the first years. They were all young and either had their heads buried in books while they waited or they were chatting consistently with their friends. She hoped she didn't get the chatting ones. She hated meaningless chatter. She looked at Alex and Cristina, and could tell that they were think ing the same thing.

She looked around, and saw that there was about an even amount of students as there were tutors, and they'd probably get one, maybe two, each. She saw a man putting up a list of names with two columns, and when she got a closer look, she saw that she had Lexie Jackson. How the hell am I going to find her? There must be at least twenty first year girls in this room. She scanned the room uselessly until she finally realised that they were all wearing name tags. She had two thoughts when she realised that. One was thank God, or else I'd be here so long I'd miss my anatomy class. The other one was thank God that i didn't have to wear a name tag.

"Lexie Jackson?" Meredith asked, looking at a small dark brown haired girl with big brown eyes.

"Yeah, are you Meredith Grey?"

"Yup."

There was an awkward silence until Meredith decided she should get to know her a bit.

"Are you a chatter?" She blurted out.

"What?" Lexie asked, confused.

"Never mind. What classes are you taking?"

They continued to talk easily, Meredith checking her watch every five seconds to make sure she didn't miss her class.

"Well, I have an anatomy class now. I'll, um, see you later." Meredith mumbled, and turned to go.

"Wait, don't you want my number? So you can, you know, tutor me?"

"Right! Sure. Um, do you want to right it down...um..." Meredith said, rummaging through her bag for a pen and paper. She found a pen and gave it to Lexie.

"Just write it on my hand. I'll call you tomorrow some time. It was nice meeting you, Lexie." Meredith said, and turned around. Lexie wasn't too bad. She wasn't a chatter, and she seemed really smart, which was helpful. Now Meredith just had to channel her inner teacher (if she had an inner teacher) and find out how to..well...teach.


	3. Chapter 3 She Will Be Loved

**Chapter 3: She Will Be Loved**

**A/N: Hey guys :) In this chapter, you have to remember that Derek and Mark are just residents in this fic, so they are surgery hungry, and they are trying to get every one that they can, so just keep that in mind. Thanks for reading! Please review :)**

Derek sat down beside Mark in the cafeteria, slamming his tray down on the table, making a loud bang.

"Hello. Way to make an entrance." Mark said, looking around at the people from the tables nearest them looking over at the loud noise.

"I'm pissed off. Don't joke with me. I'm tired and I'm pissed off because I was late getting here and I now I have to chart and be in the pit all day." Derek said, grabbing some fries.

"Well, I guess you should have thought of that before you decided to stay up all night with that slut you brought home." Mark said jokingly. Derek almost laughed, thinking that that was the only time he'd ever heard Mark talk trash on his little sister, but he covered it up with a small smirk.

"Ah, there you go. That's almost a smile. See, you only have to be around my brilliance to forget all about your crappy day charting in the pit." Mark said, smiling triumphantly, while Derek's small smile faded into nothing when he remembered what he had to do for the rest of the day.

"God, I hate charting. It never ends! Every time the patients blood pressure goes down the slightest bit, I have to record it. And you know, would say it was a slow day in the pit, but then everyone in the ER would kill me cause then I'd jinx it and we'd get like eleven really bad traumas." Derek ranted.

"But that means lot's of cool surgeries. Go ahead say it, and then pretend you forgot about the jinx or something. And then you'll get eleven trauma cases to choose from." Mark said, as if this was the obvious thing to do.

"Wow, Mark, what a great idea! Eleven trauma surgeries and we have four available OR's in the hospital. That means that seven of them will die. But thats okay, at least I got a cool surgery, right?" Derek said sarcastically.

"Whatever." Mark retorted, obviously annoyed that he couldn't come up with a better comeback. "So, what time do you get off? You gonna call that hot redhead who gave you her number last week? You should, man. Or at least give me her number. You shouldn't waste a good chick just because you're depressed." Mark said, smiling.

"I don't know. She's not really my type...plus she's a resident at Mercy West, so it would be nearly impossible trying to find a night we are both off...Here, you can have her number."

"Your excuses suck. But I'll take her number anyway." He said, taking Derek's phone and texting himself the number.

Derek's pager went off, and he looked at it quickly and groaned.

"I have to go back to the pit. Seriously, I don't care if you call the redhead or not. In fact I insist on it, because maybe she'll be so amazed by the Sloan method that she might forget she gave me her number in the first place." Derek said, standing up and picking up his tray.

"And my excuses do not suck." He added, and then turned away in the direction of the pit. Mark smirked, shook his head, and went back to his lunch.

(...)

Meredith walked into her house after a long day of classes and thinking about how to teach Lexie. She was tired and she was looking forward to a long relaxing bath and ordering in some pizza. She was craving cranberry juice, so she started running the bath and went to grab her drink. She quickly drank the juice, and as if her day wasn't already crappy enough, she accidentally spilled a bit on her new blouse. "Shit." She muttered, and pulled it over her head. "Crap, crap, crap! You are such a klutz, Meredith." She said to herself, running the blouse under water and scrubbing at it.

"Talking to yourself now?"

Meredith jumped about a foot off the ground and spun around.

"Derek! You, ah, you scared me." She said, turning back to the sink, suddenly uncomfortable. Tell him, you have to tell him, she thought. He's Marks friend, you shouldn't have gotten involved with him in the first place...but he's so dreamy...and his eyes...and that hair...

Meredith's thought process was cut off abruptly when Derek walked over to her and slid his arms around her waist.

"What, uh, are you doing?"

"I'm trying to kiss you." He said, in between kisses on her neck.

"I know, I mean what are you doing here? In my house?"

"Well, I had a crap day and I wanted to see you. So I decided to use the key you left under the mat and come over to your house, because we are always at my house. I thought it would be nice for a change." He said, putting his head on her shoulder and still hugging her.

"I, well, there's, you know there's a reason we are at your house. I don't have men at my house because it's one of my -"

"I know, I know. It's one of your rules. Can't you break the rules? For me?" He turned her around so she was facing him, and gave her his best smile, making her lose herself in his eyes for a second.

"I, they are rules. I can't break my rules. Not for anyone. And especially not for you." She said, raising her eyebrows.

"Come on. Rules are made to be broken..." He said, kissing her on the lips before she could retort back at him. She kissed him back for a second before raising her hands and slapping his face away from her and breathing heavily. He smiled back at her and she glared at him.

"I need you to go."

"You know what I think? I think that you hid your key in the most obvious place in the world just so if I ever came for a surprise visit I would know how to get in. I think that subconsciously, you love me."

"Shut up! I do not love you! The only reason I hang out with you is because of the sex, because we both want the same thing. A meaningless relationship...with no strings attached. Right? You still don't want strings?"

"You really think we have a meaningless relationship? Seriously? We spend pretty much every night together, and less than half of that time is having sex."

"Yes. I'll give you that. Most of the time we are sleeping." She said, rolling her eyes.

"Yeah, we're sleeping, but most of the time we are talking. You and I have more in common and fit together better than any other girl I've ever been with."

"The sex is just good. You are delusional if you thought I'd ever agree to something more!" She said, moving out of his embrace. She walked around the breakfast bar and sat down facing him.

"Look. We had a misunderstanding. You thought that we were more than we are. But I can't give you more. That's not what I wanted when I got with you in the bar in the first place."

"I know you feel it too. I can't believe how stubborn you are! It's crazy. And you're crazy if you think I'm going to let you get away." He said, and gave her one last glance before walking out the door.

Meredith watched as he slammed the door behind him. "Crap." She said, sliding her face into her hands.


	4. Chapter 4 Who Says You Can't Go Home

**Chapter 4: Who Says You Can't Go Home**

**A/N: I know. Trust me, I know. It has been an awfully long time since I have updated, and I am so sorry about that :( I have been so busy lately, and I have had absolutely no time to write! I hope this update is worth it, and I will try to update more frequently! Thanks for reading x**

Meredith woke up the next morning after their fight a little dazed. She looked around her, and before coherent thoughts could form in her mind, she wondered why she was in her bed, not Derek's. Quickly the events of last night started to come back to her, and her eyes filled with tears. She quickly shook her head and wiped her eyes, embarrassed even though she was the only one in the room.

She sat up abruptly and felt a little dizzy before standing up and walking over to her closet. Still dazed from sleep (or lack of sleep) she grabbed the pair of jeans and top that were closest to her, and threw them on, grabbing her hair brush as she walked out the door. She had to take a second to search her fuzzy mind to see if she had any classes or appointments today. She finally concluded that she didn't and made her way down the stairs. She passed her mothers den that was still filled with her and Thatchers miscellaneous stuff, and she made a mental note to start to tidy some of the old junk up. She walked into the kitchen to find Alex sitting at the table eating cereal out of the box and reading the newspaper.

"Hey, Mer." Alex mumbled in between gulping from the milk container and stuffing cereal in his mouth. Meredith rolled her eyes and greeted him. Alex swiveled on his chair turned towards her, watching her open a box of Captain Crunch.

"Can I ask you a question?" Alex said cautiously.

"Well, that was technically a question anyway so...ask away."

"Why were you up at 4am this morning having a shower and then watching TV?"

"What? Oh. Um...I couldn't sleep. Lot's of...things on my mind. I was thinking about...things...and I couldn't...um...stop. Thinking, I mean. I couldn't stop thinking." Meredith said lamely. When Alex raised his eyebrows at her, she turned away from him to the fridge to get some milk.

"Okay. Now tell me why you were _really_ up at 4am this morning having a shower and watching TV." Alex smirked.

"I just told you! I was thinking. I couldn't stop thinking."

"Right. What were you thinking about?"

"It's nothing..." Meredith avoided, and poured the milk into her cereal. Alex shrugged and was about to turn back to his newspaper when Meredith turned to look at him.

"It's just...his eyes. And his hair. And the things he says...Damn. I'm so falling for him! Stupid, stupid Meredith. I can't believe this. I'm _that_ girl, aren't I? I'm the girl who swoons, and says cheesy things, and calls him first, and...Oh God, my life is becoming a soap opera. I can't believe this! Stupid McDreamy with his eyes, stupid boy penises..." Meredith ranted.

"Wait, what? Who are we talking about?" Alex asked, confused.

"Derek, goddamnit! Derek Christopher Shepherd."

Alex still looked at her quizzically, so she clarified it by reminding him about the $150.00 anatomy book.

"Ahhh, _that_ Derek! Right, I'm with you now. Kind of..."

"And then theres the Mark thing. Why can't Mark be a normal brother? Not an overprotective idiot who thinks I have to have his _permission_ before I can date anyone? He is so cautious when it comes to who I sleep with, but he is sleeping with anyone with a pulse! And then there's the fact that I have these stupid rules. The rules that I promised I wouldn't break, and he's almost convincing me to break them? Ugh, what is wrong with me? Alex, seriously, I need you to answer me..."

"Answer you...How am I supposed to do that? I'm not a chick, I don't speak your language. Hell, I'm not sure if half of what you just said was english..."

"Will you just get over yourself for one second and help me out here? Come on, just...I don't know, be Cristina for me or something!"

"Um...okay. I'm channeling Cristina...so...I think that she would say...a man does not define who you are?" Alex said, looking like he was concentrating really hard.

"She would so not say that, but that helps, thank you. You're right. I did the right thing. A man does not define who I am...I am my own person."

"Well, you're gonna be a hungry person if you don't eat the soggy cereal you've been holding for the last ten minutes. I have to go. I have to meet up with my first year." Alex rolled his eyes.

"So you didn't get a hot chick?" Meredith smirked, calming down a little.

"Well, yeah, she's hot, but I have no idea how she got into UW, she has no brains. I bet if I asked her what specialist you would need for a brain aneurysm, it would take her half an hour to come up with 'neurosurgeon'."

Meredith laughed, her mood lightening. "I really should call Lexie...if I find her number. I wrote it down somewhere..."

"You wrote it down _somewhere _that's helpful..."

They talked a bit more before Alex had to rush out the door, because he was already ten minutes late. Meredith liked Alex, he was fun to talk to and when he wasn't being an ass or a perve, he was a great friend.

Meredith started to clean the dishes when she heard a knock on the door. She walked over to the door and wiped her wet hands on her jeans. She didn't look up to see who it was, and instantly regretted opening the door as soon as she saw who it was.

"Dad." Meredith said in a deflated tone. Just as her day was getting a bit better, Thatcher had to turn up.

"Meredith...Hi sweetie. How are you darling?" He said, smiling a little to widely.

Meredith looked him up and down. Drunk. He was definitely drunk. The tone of his voice was to happy for him to be sober. As she stood there staring at him, she contemplated calling Mark. She knew he said that whenever she needed him, he'd be there, but she didn't want to disturb him at the hospital, she knew how hard he worked. Anyway, he's 'happy drunk' not 'hit-everything-within-reach drunk'. She could handle this. She stepped aside and he walked in. She realised suddenly that she hadn't answered his question.

"I'm fine Dad. What are you doing here?" She said in a careful tone, knowing all too well how easily his 'happy drunk' can turn into something much more violent, and he was set off by the slightest things.

"You know...I was just...in the neighborhood."

"But, Dad, you live in Atlanta..."

"I know that!" He said in a harsh voice, and Meredith took an instinctive step back. Thatchers face softened, as if realising that he was scaring her.

"I know, sweetie, I was just in town and I thought I'd come see my Meri..." He stepped forward and wrapped his arms around her. She grimaced, and she wasn't sure if it was because of the fact that the man who had caused her so much pain in childhood had just hugged her, or the fact that that same man had used his pet name for her, as if no time had passed, as if she still...loved him.

When he released her her mind told her that something was different, but before she could think more about it, she saw a figure through the screen door. He was just standing there, watching them, his mouth slightly open and his hand stretched forward, as if he was considering coming inside but thought against it. She made eye contact with him and slightly shook her head and put her hand on Thatchers shoulder.

"Would you like go into the kitchen? I was just about to start some coffee." When Thatcher nodded his head, Meredith smiled.

"You go ahead, I'll be there in a moment." She said, and walked around him to the staircase. She watched him go inside the kitchen and close the door before she walked back towards the screen door and opened it quietly. "Derek, what are you doing here?"

**I'm sorry for the small cliffhanger at the end, it just seemed like the best place to leave off. I'll try to update soon/more. Please let me know what you think x**


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